Previous processes for identifying multiple individual loads supplied by a common AC power service use measurements of electrical parameters of only the common supply. These parameters are digitally measured for each alternating current (AC) supply cycle, e.g., 60 samples per second in North America. The loads are identified using the time dependent behaviors (referred to herein as time traces) of the first few seconds of the turn-on positive transition of these parameters. Most devices found in residential and light commercial buildings produce unique time traces. These devices can be identified and tracked using a time trace disaggregation process (referred to herein as a TTDP process).
Many devices identified and tracked in residential and commercial buildings have motors and connected machinery that consume substantial energy. Some of the various types of examples include refrigerators, air conditioners, pumps, and fans. The operations of these devices are often taken for granted and, unfortunately, the devices are usually not serviced until they fail.
Such failure is usually progressive and accompanied by a loss of efficiency. For example, a common failure mode of air conditioners is slow leakage of the refrigerant. As the refrigerant leaks, the air conditioner becomes less efficient and must run longer to produce the same amount of cooling. Eventually, the air conditioner runs continuously because it can no longer maintain the set temperature. It may take days, weeks, months, or even years for complete failure to occur. During this time, the building occupant may not notice the increase in energy usage or, if he or she does take note, attribute the increase in energy use to changes in weather or some other reason. Hundreds or even thousands of dollars may be wasted before the problem is detected, let alone fixed. Further, the problem or failure is most likely to be detected on a hot day when service is unavailable because other systems have failed and all available service technicians are already busy.
Some progressive failures do not affect efficiency but do affect reliability. A necessary component typically degrades until it causes complete failure. Refrigeration and air conditioning in some commercial buildings are required for operation. In such settings, failure may cause loss of goods and/or business. While this equipment may be covered by a service agreement and even checked on a regular bases, the failing component may be difficult to check.
For example, many motors use a start capacitor for 0.1 to 1 second while starting. If the capacitor begins to fail, the motor will continue to start until an operating threshold is reached. Eventually, the motor will not start. This type of failure is usually abrupt.
As another example, large power loads such as air conditioners are generally turned on and off by a mechanical relay. Such relays typically fail because the contacts erode due to arcing. The arcing generally occurs only during startup, so the load may continue to start until a contact completely fails.
Capacitors and relays are relatively inexpensive components. In fact, such components typically have a cost that is much less than that associated with a service call to replace them. If a pending failure of such components were known or identified, the components would desirably be replaced during a scheduled maintenance visit. This would significant increase the reliability of the equipment while reducing the total overall maintenance cost.
While individual devices can be equipped with monitors that detect inefficient operation and potential failures, these devices are typically expensive and generally cost-effective only in certain special cases. Therefore, there remains a need for an inexpensive process that monitors the operating efficiency and pending failures of common electrical devices found in residential and commercial buildings.